Low-voltage synchronized BPF-based cascaded VSI controller in solar-wind powered small-scale isolated hybrid microgrid for rural electrification

Rural electrification through low-voltage in isolated hybrid microgrids, with distributed renewable resources (DERs), contributes to sustainable development by offering reliable, decentralized and scalable electricity. However, this approach alleviates burden on the main grid and fosters socio-economic development. This requires an effective controller for efficient power management and maintaining voltage & frequency. The inherent challenges of low-voltage microgrids, power quality exacerbation by the non-linear loads, along the dynamic nature of DERs, underscore the complexity of these systems. The proposed work introduces a low-voltage synchronized bandpass filter-based cascaded PR controller for a single-phase isolated hybrid microgrid. This design aims to address the discussed research gaps and support various loads & applications for small-scale rural electrification. The system incorporates 3 kW wind and 2 kW solar energy generation, complemented by battery management systems and VSI to handle AC nonlinear loads uninterruptedly. It is designed to maintain the THD level within IEEE 519 standards and is tested with variable conditions for non-linear loads using several case studies. A comprehensive analysis is presented to show effective power management, precise voltage and frequency regulation. The laboratory hardware setup validates the VSI controller's real-world applicability for non-linear load maintaining THD level within standards.